They stay moist for up to 12 hours! These paints offer a unique set of working properties that represent a true starting point, leaving all other acrylic paints on the market behind, dramatically expanding the range of possible techniques available to acrylic medium painters. OPEN Acrylics paints feature an optimal balance of pigment loading and 100% acrylic polymer dispersion, with unique working characteristics coupled with versatility that allows artists to explore traditional techniques, such as portrait and landscape painting, that rely on smoothness, shading, varnishing and fineness of detail. OPEN Acrylics are resistant to the formation of lumps, remaining wet for a long time on the palette, and can be used directly from the tube when painting outdoors or when making monoprints and screen prints. OPEN Acrylics paints can be mixed with GOLDEN Acrylic Colors, Mediums and Gels to control working time. For maximum working time use OPEN Mediums and Thinner. 236ml capacity plastic bottle in opaque hansa yellow.